Method of producing bearing rings



Patented June 13, 1950 UNITED STATES PATENT oFr-'lcE METHOD OF'PRODUCING BEARING RINGS Harold R. Gibbons, Chatham, N. J., assignor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application June 16, 1945, Serial No. 599,871

1 Claim.

Fig. l is a sectional view taken axially of a roller bearing race ring.

Fig. 2 is a cross sectional view of the race ring press-fitted on a shaft.

Figs.` 3, 4 `and 5 are diagrammatic sections of race rings of different characteristics.

in Fig. 1 is shown a race ring 2 having a curved raceway d for cooperation with rollers of a barrel roller bearing but the invention is applicable to bearing racerings generally. Such race rings have a, cylindrical bore 6 for mounting on a shaft 8. They are commonly'made v`either of low carbon, Acase `hardened steel or of through-'hardening high carbon steel.

with case hardening indicated at c I2 lby the shading.` .Such a ring may 'be mounted onine pered area or thinner section extends outwardly from the bore for a relatively small proportion of the ring thickness and directly joins the thicker section without any abrupt line of demarkation or interposed annealed or third layer which is a fertile source of spalling or exfoliation in the use of hardened articles. Instead, the thinner section is softened and made more ductile by tempering and becomes less soft in an outward direction from the bore until it joins,

and attains the hardness of, the thicker bodyY section. This tempering is conveniently accomv2() `In Fig. 3, the ring -I9`is of low carbon steel sliait ywith a'heavy press nt so that a :clamping Tuut-or other securing means is unnecessary. ,'.High

Ahoop stresses are Jbytherpressdt but diameter 'to the fbore asindicatedby the curve C "in Fig. 2.

If a through hardened, high carbon race ring.

such as indicated `at i6 in Fig. 'tbe-mounted onA a shaft with aheally pressiit, the' high hoop stresses at, the bore are 'liable to crack the race ring or induce a crack becauseoi `the brittle naturelof the metal. Hence heavy press nts for such rings are precluded and other securing means is necessary `for' such rings or has been considered essential. y

According to my invention, the race ring I8 of Fig. 5 is made of high carbon, throughhardening steel, hardened and tempered throughout, followed by a superimposed or second tempering upon its bore portion only as indicated by shading at 20, leaving the greater portion or thicker section of the ring substantially unaffected. The second tempering is of course at a higher temperature than the rst one applied to the through-hardened ring. The last temso 2.368.007

pllshed by induction heat treatment which quick- 1y heats only the bore portion. The ring is then allowed to cool or, if thin in section, it maybe cooled by a.v spray to retard heat conduction into the body of the ring. A suitable steel is A. S. M. E. 52100 which is good and clean and readily available. By the use of this steel treatednasnabove. .slow carburizing treatment of low carbon steel is avoldedyet thehody of Vthe race ring Vretains a hardness of Vabout 57 '1:0'64' Rockwell C whileits bore 2is rendered soft and ductiie to AWithstandaihren/y press 'nt withvout cracking.

"The:metnmil ...of fproducing. an .inner -race ring for .antifretionibearings and .mounting 1t on a shaft which consists Yin .making the .Ting high l0 carbon, through-hardening Vsteel,"hardening and ...tempering the entire ring,.giving the 'bore kpor-- tion of the ring a superimposed or second tempering at a higher .temperature than Vthe .mst temperature .torender' it softerand more ductile a5 than themajor portion-.of the body. and pressfitting thesoit and ductile bore perdonen-.n shaft.

V'HAROLD 115'.. GIBBONS.

` REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 45 Number Name Date 1,793,232 Gray Feb. 26. 1929 2,145,864 Deneen Feb. 7, 1939 2,259,324 Robinson Oct. 14, 1941 2,281,332 Somes Apr. 28, 1942 Delahan Jan. 23. 1945 

